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Class 10 Chemistry Chapter 25 Biochemistry Class Test 2 PDF | Punjab Board 2027
Grade 10 Chemistry Chapter 25 Biochemistry Test 2
Class 10 Chemistry Chapter 25: Biochemistry – Class Test 2 is part of the Punjab Board 2027 Model Papers series, prepared according to the new syllabus issued by PECTAA Punjab. This chapter-wise test is designed to help students prepare for their Class 10 Chemistry examinations through focused practice. Students can use this Class 10 Chemistry Chapter 25 Biochemistry test to revise important concepts, practise exercise questions, and prepare for the full unit test. Explore our Class 10 Chemistry Chapter Wise Test Series, including the full unit test with exercise questions, to strengthen your exam preparation.
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CHEMISTRYCHAPTER-25 (OBJECTIVE)CLASS TEST-2
1- Lipid provide average more energy than carbohydrates or proteins
(a) 1.5 times
(b) 2 times
(c) 3 times
(d) Same
Answer: (b) 2 times. Fats give about 9 kcal/g, while carbohydrates and proteins give about 4 kcal/g.
2. An adult consume proteins per day is
(a) 40 g
(b) 50 g
(c) 60 g
(d) 70 g
Answer: (d) 70 g (as per the textbook figure; recommended values vary slightly between sources).
3. Molecular formula of glucose is
(a) CHO
(b) C2HO6
(c) C6H12O6
(d) C12H22O11
Answer: (c) C6H12O6
4. The phenomena in which proteins structure is changed:
(a) Fermentation
(b) condensation
(c) Denaturation
(d) Neutralization
Answer: (c) Denaturation. Heat, acids or alkalis destroy the natural 3-D structure of a protein.
5. Fatty acids usually contain carbon atom
(a) 6-10
(b) 10-14
(c) 12-28
(d) 30-50
Answer: (c) 12-28
6. Carbohydrates, proteins, fats and water make together constitute the living organism
(a) 90%
(b) 95%
(c) 97%
(d) 99%
Answer: (d) 99%
7. Mass of RNA molecule is
(a) 300 Da
(b) 340 Da
(c) 400 Da
(d) 660 Da
Answer: (b) 340 Da (average mass of one RNA nucleotide; 660 Da is for a DNA base pair).
8. Main purpose of gene therapy is
(a) fight disease
(b) stop growth
(c) change colour
(d) destroy cells
Answer: (a) fight disease
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CHEMISTRYCHAPTER-25 (SUBJECTIVE)CLASS TEST-2
Attempt any 10 Questions.10×2=20
i.
Write the names of major classes of food and their importance.
Major classes: carbohydrates, proteins, fats (lipids), vitamins, minerals and water.
- Carbohydrates: main source of energy.
- Proteins: growth and repair of body tissues; enzymes and hormones.
- Fats: concentrated energy store, insulation, carry fat-soluble vitamins.
- Vitamins & minerals: regulate body processes and prevent deficiency diseases.
- Water: medium for reactions, transport and temperature control.
ii.
How much carbohydrates are required per day?
Ans: An adult needs roughly 300-500 g of carbohydrates per day, depending on age, sex and physical activity (about half or more of the daily energy intake).
iii.
Write the application of vitamins or mineral.
Ans: Vitamins act as coenzymes and protect against deficiency diseases (e.g. vitamin C prevents scurvy, vitamin D prevents rickets). Minerals build bones and teeth (calcium, phosphorus), form haemoglobin (iron) and regulate nerve and muscle function (sodium, potassium).
iv.
Which function perform balance diet?
Ans: A balanced diet supplies all nutrients in the right proportion. It provides energy, builds and repairs tissues, regulates body processes, maintains health and protects from disease.
v.
What is proteins?
Ans: Proteins are high-molecular-mass biopolymers made of many amino acids joined by peptide bonds (–CO–NH–). They contain C, H, O, N and often S.
vi.
What is polypeptide?
Ans: A long unbranched chain of many amino acids linked by peptide bonds is called a polypeptide. One or more polypeptide chains form a protein.
vii.
Which foods are rich sources of vitamin A? Write its deficiency symptoms
Sources: carrot, spinach and green leafy vegetables, milk, butter, egg yolk, fish liver oil, liver, mango and papaya.
Deficiency: night blindness, dry eyes (xerophthalmia), rough dry skin and poor resistance to infections.
Deficiency: night blindness, dry eyes (xerophthalmia), rough dry skin and poor resistance to infections.
viii.
How DNA different from RNA?
- DNA: double stranded; sugar is deoxyribose; bases A, T, G, C; found mainly in the nucleus; stores genetic information.
- RNA: single stranded; sugar is ribose; bases A, U, G, C; found in nucleus and cytoplasm; helps in protein synthesis.
ix.
What is the purpose of pregnancy test and how can measure?
Ans: It confirms pregnancy. The test detects the hormone hCG (human chorionic gonadotropin) in urine or blood. Antibodies on the test strip bind hCG and give a coloured line; blood tests can measure the hCG level quantitatively.
x.
What is gene therapy?
Ans: Gene therapy is the treatment of genetic disorders by inserting, replacing or repairing defective genes in a patient’s cells with healthy ones.
SECTION-II
1.
Draw open chain structures of glucose and fructose.
Glucose (open chain)
C6H12O6 – aldohexose
C6H12O6 – aldohexose
Fructose (open chain)
C6H12O6 – ketohexose
C6H12O6 – ketohexose
Note: Glucose has an aldehyde group (–CHO) at C-1; fructose has a ketone group (C=O) at C-2. Both have the same formula but different structures (isomers).
2.
What are DNA and RNA? Describe the role played by them in our body.
DNA (Deoxyribonucleic acid): a double-stranded helical polynucleotide made of deoxyribose sugar, phosphate and the bases A, T, G, C.
RNA (Ribonucleic acid): a single-stranded polynucleotide made of ribose sugar, phosphate and the bases A, U, G, C.
RNA (Ribonucleic acid): a single-stranded polynucleotide made of ribose sugar, phosphate and the bases A, U, G, C.
- Role of DNA: stores and transmits genetic information from parents to offspring; replicates before cell division; carries the code for making proteins.
- Role of RNA: mRNA carries the code from DNA to ribosomes; tRNA brings amino acids; rRNA forms ribosomes – together they carry out protein synthesis.
